| Author |
 Replies: 10 / Views: 2,586 |
|
|
Bedrock of the Community
Australia
21786 Posts |
Is there any information concerning this question? Often when reading threads regarding fake coins, the question of weight arises. Has any good research been done concerning the wear on a coin relative to the loss of weight? What is needed to answer this question is some information on the nominal weight of a coin and the Mint's Weight Tolerance for that coin. When that is known, a graph or table for each denomination can be devised, which compares the condition of the coin verses the weight of the coin. This information than then be compared to a coin that is suspected as being a fake. |
|
|
|
Pillar of the Community
United States
3592 Posts |
Good question. When I weigh a suspect coin that is worn, I take another coin of the same denomination/wear and weigh it for comparison. It might not be scientific, but it has worked pretty well for me.I should have saved the data for future reference but it never occured to me not to be able to repeat the process.
|
|
Pillar of the Community
United States
6384 Posts |
I weighed a bunch of worn Barber quarters awhile ago and the lowest weights were around 5.85 grams (for coins in AG to Good condition). Since the standard weight is 6.25 grams these quarters were down 0.4 grams or 6.4%. I presume that would represent the upper end of the weight loss spectrum for typical worn silver coins. |
|
Bedrock of the Community
 Australia
21786 Posts |
Is there any record of such research in any American numismatic journal?
|
|
Rest in Peace
United States
9104 Posts |
Doubtful, because there's so much room for inaccuracy that it would be wasted time. For a coin to be 10% light, it has to almost be worn flat. People ask about weight on suspected coins mainly to tell if the wrong metal was used, and even then, only the most obvious variances are going to show up. For example, an Asian buyer offered a "platinum" bar on ebay. He listed the dimensions, and the only way it could have been platinum was if it was hollow. It was the right weight to be silver, tho. |
|
Bedrock of the Community
United States
20753 Posts |
Any such attempts to come up with a standard for wear is really almost impossible since not all coins are the same, get the same wear, contain the same material, etc. For example as already noted a Barber quarter lost a real lot of weight. And someone not long ago posted a Barber dime that lost almost a third of it's weight. If you look at even Cents which are made of Copper, not Silver, those too can loose massive amounts of weight from wear. Of course those Silver coins with holes drilled in them too weigh much less.  Sure would be funny to find a counterfeited Silver coin that weighs more than the original.  |
|
Moderator
 United States
23522 Posts |
Keep in mind the relative amount of metal displaced into devices, as opposed to what remains in the fields. Devices only cover, what? 30-40% of fields in complex coins? And their relative thickness by comparison to the original planchet?
I'd suggest that, as a guess, no more than 20% of the total original planchet weight ever becomes a "device." and, furthermore, even if all you can see is the outline of the original letters, stars and devices, then the majority of the original metal displaced into them remains.
The moral of the story? 5% is the point at which I start worrying about weight, regardless of wear.
|
|
Pillar of the Community
Australia
2830 Posts |
I wish I could quote my source:
the Sovereign is a British gold coin, first issued in its current form in 1817.
In the 1880s, it was decreed that any "old" sovs coming to the banks were to be withdrawn and sent back to the mint.
"Old" was defined as pre-Victorian. This is thought to explain why sovs of the earlier area are not available in large numbers.
Anyway, the story as I read it had some information about how much "under" the older coins had become, but I don't recall that detail, sorry.
Anyway, the point is that some work has been done, at least in relation to sovs.
In my limited experience of counterfeits of silver coins, the weight is usually way off.
I have a nice fake crown, which ought to be 28g or so, but it is only 19g, and magnetic.
I wouldn't get hung up on a gram or two.
Peter in Oz
|
|
Bedrock of the Community
United States
20753 Posts |
Quote:
In my limited experience of counterfeits of silver coins, the weight is usually way off.
Far from true with many China made Silver Dollars. Many are just as pure Silver as the original since they are being made to sell as numismatic coins, not Silver. Therefore the wieght is of no use determining authenticity and they well know that. And now that they are making faked slabs for their fake coins, you could really get messed up trying to figure out if real or not. |
|
Pillar of the Community
Philippines
1156 Posts |
I do collect fakes, not by intention but by accident, because the fakes which manages to slip and get bought are usually good ones. So great for study. Have seven "silver" fake world crowns now, and they all weigh in the range of 18 to 21 grams, as compared to the real crowns which are in the 26-27gram weight so if I'm looking at a nice "genuine" silver world crown but it weighs in at 20 grams or so, I'd be concerned  |
|
Rest in Peace
United States
9104 Posts |
Like most electronics, scales are dirt cheap to the point where any serious collector should carry a pocket scale. US balance makes one that will weigh 1000 grams to .1 gram or five other modes. Costs a fortune, about $12 at harbor freight. For example, .1 gram is 1/50th of a nickel, or .1 gram of pure gold is $4.50.
|
| |
Replies: 10 / Views: 2,586 |
|
Posted 02/26/2011 11:59 pm
